Investigation of the electric field structure in neutral-beam-heated ISX-B plasmas

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5086839

Mathew, J

Plasma potentials were measured for the first time in neutral beam heated tokamak discharges. Radial potential profiles were obtained for coinjection, counterinjection, and balanced injection discharges as well as for ohmically heated plasmas in the Impurity Study Experiment (ISX-B) tokamak. Within experimental uncertainties, the measured values of potential are consistent with calculations based on radial momentum balance using experimental values of rotation velocities, density, and ion temperature. The measurements were made using a heavy ion beam probe, with typical plasma conditions of I/sub p/ approx. = 150 kA, B/sub T/ approx. = 12.3 kG, n/sub e/ approx. = 4 x 10/sup 13/ cm/sup -3/, and P/sub b/ approx. = 0.9 MW. A negative potential well depth of about 1.0 kV was observed in ohmically heated plasmas and increased somewhat for balanced injection. Counterinjection resulted in a significantly larger well depth approximately 3-4 kV, while coinjection showed an outward pointing electric field in the plasma interior. In ohmically heated plasmas the potential was constant in time, but significant time variations in potential were observed in neutral beam heated discharges. Potentials in ohmic plasmas showed both a density and a plasma current dependence. There was an observed improvement in the particle confinement times of both ions and impurities with counterinjection as compared with coinjection.

• Research Organization: Rensselaer Polytechnic Inst., Troy, NY (USA)
• OSTI ID: 5086839
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700101 -- Fusion Energy-- Plasma Research-- Confinement
Heating
& Production
700102* -- Fusion Energy-- Plasma Research-- Diagnostics
BEAM INJECTION
BEAM INJECTION HEATING
CONFINEMENT TIME
DATA
ELECTRIC POTENTIAL
EXPERIMENTAL DATA
HEATING
INFORMATION
ISX TOKAMAK
NEUTRAL ATOM BEAM INJECTION
NUMERICAL DATA
PLASMA HEATING
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS